DEEP CLEANING SET FOR SAN DIEGO BAY

Long-planned dredging effort would remove contaminated sediment

San Diego Bay is scheduled for a deep cleaning next month when shipyards south of the San Diego-Coronado Bridge will dredge contaminated sediment to ensure healthier waters.

Toxic materials from industrial operations and urban runoff have built up over decades, settling in the sediment. They are absorbed by small animals, fish and eventually people, especially people who fish frequently in the area.

The dredging effort would remove 158,000 cubic yards of contaminated sediment from the area in front of the BAE Systems and General Dynamics NASSCO shipyards near the bridge.

“San Diego Bay is an area of national importance,” said Dave Gibson, executive officer of the San Diego Regional Water Quality Control Board, which issued the cleanup order last month. “It is one of the most commercially important bays, and it is an important military base. So cleaning that up is one of the board’s highest priorities.”

While modern shipyards employ environmental controls to reduce contamination to the bay, the companies, along with other bay users and the port district itself, are responsible for cleaning up decades of previous pollution.

The plan targets heavy metals and other industrial chemicals that harm humans or marine life. It will employ a large “clamshell” shovel to capture and enclose the material, and will dry and ship it to landfills.

But the dredging, scheduled to start in mid-September, is still subject to disputes among the port district, shipyards and other users over who is responsible for the cleanup bill, estimated at $75 million. The cleanup has been a work in progress for 20 years, as agencies argued over the extent of the contamination, the areas for dredging and the cleaning bill.

“The cleanup is not as stringent and protective as we wanted it to be,” she said. “But they are getting the worst of the worst out of the bay, and I think that’s very important. Because they’re removing the source of their contaminants, at least we have a fighting chance to put San Diego Bay on the road to health.

Before the last century, “San Diego Bay was a fertile, shallow bay supporting tremendous biodiversity in its open water, salt marshes and mud flats,” the Environmental Health Coalition stated in an online document.

As the area urbanized, industrial, commercial and military operations cropped up along the shoreline, stirring up what environmentalists have called a “toxic soup” of contaminants.

“Navigation channels were dredged. Mud flats and salt marshes were filled,” according to the coalition’s document. “More than 90 percent of the mud flats and 78 percent of the salt marshes were eliminated, and those that remain are found mostly in South San Diego Bay.”

While the bay front drove a thriving marine economy, it had its costs as well. Heavy metals built up in the bay floor, including mercury and lead — both potent poisons to the human neurological system — and copper, which is toxic to shellfish.